Rtc ds3231 for Raspberry Pi 2 Model B

Question

I am trying to install Hwclock RTC DS3231 on my Raspberry Pi 2

Below are os version.

NAME: Raspbian GNU/Linux
VERSION_ID = 7
VERSION="7 (whezy)
ID = raspbian
ID_LIKE = debian

Step taken by me.

1. sudo cp /etc/default/hwclock /etc/default/hwclock.BAK
2. less /boot/overlays/README
3. scroll to the i2c-rtc section and find the crossponding parameter for me it was ds3231
4. sudo nano /boot/config.txt
5. Added dtoverlay=i2c-rtc,ds1307
6. Save and exit from nano editor.
7. sudo nano /etc/modules
8. Added i2c-dev, i2c-bcm2708 rtc-ds3231
9. Save and exit from nano editor.
10. reboot
11. sudo apt-get install i2c-tools
12. sudo dpkg --purge fake-hwclock
13. sudo i2cdetect -y 1
14. sudo nano /lib/udev/hwclock-set

15. Code:

    dev=$1
    
    #if [ -e /sys/fs/cgroup/systemd ] ; then
    #    exit 0
    #fi
    
    #if [ -f /etc/default/rcS ] ; then
    #    . /etc/default/rcS
    #fi
    
    # These defaults are user-overridable in /etc/default/hwclock
    BADYEAR=no
    HWCLOCKACCESS=yes
    HWCLOCKPARS=
    HCTOSYS_DEVICE=rtc0
    if [ -f /etc/default/hwclock ] ; then
        . /etc/default/hwclock
    fi
    
    if [ yes = "$BADYEAR" ] ; then
        /sbin/hwclock --rtc=$dev --systz --badyear
    else
        /sbin/hwclock --rtc=$dev --systz
    fi
    

16. sudo date

17. sudo hwclock -w
18. sudo hwclock -s
19. sudo hwclock -r
20. After that if I am checking the date and hwclock -r both coming correct but after reboot when I am running date its coming correct but hwclock -r it showing below message

hwclock: The Hardware Clock registers contain values that are either invalid (e.g. 50th day of month) or beyond the range we can handle (e.g. Year 2095).

Answer 1

I make some stuff with Arduino and here is the code:

void setup() {
  rtc.halt(false); //setupable rtc
  rtc.writeProtect(false); //setupable rtc
  //!!IMPORTANAT!!----!!IMPORTANAT!!----!!IMPORTANAT!!----!!IMPORTANAT!!----!!IMPORTANAT!!----!!IMPORTANAT!!
  Time t(2017, 8, 12, 10, 8, 50, Time::kFriday); //set time to rtc, then the next line uncommented, for the first time, after time is setted comment the next line!!!
//  rtc.time(t);  UNCOMMENT FOR FIRST RUN THEN COMMENT IT, IF NOT IT EVERY RUNS OVERWRITE THE TIME!!!
}

The important thing is, once you set up the time of the RTC and after it comments it because if it runs again, it will overwrite it with this date time.

The whole project is here.